[Icons NTP] Refactor large_icon_source to extract the logic shared between desktop and Android to a new large_icon_service.

This is required since the Android implementation of the icon-based NTP will rely on custom Java code to render the fallback. As a result we want to share the logic needed to retrieve large icons and to compute the fallback style without needing them to go through the full-featured chrome://large-icon that performs the rendering of fallback icons. The Java code will hook directly into the large_icon_service.

This CL also fixes a bug, making sure only non-square icons can be returned as large icons.

Besides this, this CL doesn't change the behavior but will make it possible to add the large icon selection logic to large_icon_service where it can be shared with the Android code.

BUG=467712

Review URL: https://codereview.chromium.org/1092873002

Cr-Commit-Position: refs/heads/master@{#326325}

5 files changed, 71 insertions, 8 deletions

diff --git a/components/favicon_base/fallback_icon_style.cc b/components/favicon_base/fallback_icon_style.cc
index e620613..d3e395b 100644
--- a/components/favicon_base/fallback_icon_style.cc
+++ b/components/favicon_base/fallback_icon_style.cc
@@ -4,6 +4,9 @@
 
 #include "components/favicon_base/fallback_icon_style.h"
 
+#include <algorithm>
+
+#include "ui/gfx/color_analysis.h"
 #include "ui/gfx/color_utils.h"
 
 namespace favicon_base {
@@ -12,14 +15,19 @@ namespace {
 
 // Luminance threshold for background color determine whether to use dark or
 // light text color.
-int kDarkTextLuminanceThreshold = 190;
+const int kDarkTextLuminanceThreshold = 190;
+
+// The maximum luminance of the background color to ensure light text is
+// readable.
+const double kMaxBackgroundColorLuminance = 0.67;
 
 // Default values for FallbackIconStyle.
-SkColor kDefaultBackgroundColor = SkColorSetRGB(0x80, 0x80, 0x80);
-SkColor kDefaultTextColorDark = SK_ColorBLACK;
-SkColor kDefaultTextColorLight = SK_ColorWHITE;
-double kDefaultFontSizeRatio = 0.8;
-double kDefaultRoundness = 0.125;  // 1 / 8.
+const SkColor kDefaultBackgroundColor = SkColorSetRGB(0x78, 0x78, 0x78);
+const SkColor kDefaultTextColorDark = SK_ColorBLACK;
+const SkColor kDefaultTextColorLight = SK_ColorWHITE;
+const double kDefaultFontSizeRatio = 0.44;
+const double kDefaultRoundness = 0;  // Square. Round corners are applied
+                                     // externally (Javascript or Java).
 
 }  // namespace
 
@@ -45,4 +53,18 @@ bool ValidateFallbackIconStyle(const FallbackIconStyle& style) {
       style.roundness >= 0.0 && style.roundness <= 1.0;
 }
 
+void SetDominantColorAsBackground(
+    const scoped_refptr<base::RefCountedMemory>& bitmap_data,
+    FallbackIconStyle* style) {
+  SkColor dominant_color =
+      color_utils::CalculateKMeanColorOfPNG(bitmap_data);
+  // Assumes |style.text_color| is light, and clamps luminance down to a
+  // reasonable maximum value so text is readable.
+  color_utils::HSL color_hsl;
+  color_utils::SkColorToHSL(dominant_color, &color_hsl);
+  color_hsl.l = std::min(color_hsl.l, kMaxBackgroundColorLuminance);
+  style->background_color =
+      color_utils::HSLToSkColor(color_hsl, SK_AlphaOPAQUE);
+}
+
 }  // namespace favicon_base
diff --git a/components/favicon_base/fallback_icon_style.h b/components/favicon_base/fallback_icon_style.h
index 097636b..84842ed 100644
--- a/components/favicon_base/fallback_icon_style.h
+++ b/components/favicon_base/fallback_icon_style.h
@@ -5,6 +5,7 @@
 #ifndef COMPONENTS_FAVICON_BASE_FALLBACK_ICON_STYLE_H_
 #define COMPONENTS_FAVICON_BASE_FALLBACK_ICON_STYLE_H_
 
+#include "base/memory/ref_counted_memory.h"
 #include "third_party/skia/include/core/SkColor.h"
 
 namespace favicon_base {
@@ -37,6 +38,13 @@ void MatchFallbackIconTextColorAgainstBackgroundColor(FallbackIconStyle* style);
 // Returns whether |style| values are within bounds.
 bool ValidateFallbackIconStyle(const FallbackIconStyle& style);
 
+// Set |style|'s background color to the dominant color of |bitmap_data|,
+// clamping luminance down to a reasonable maximum value so that light text is
+// readable.
+void SetDominantColorAsBackground(
+    const scoped_refptr<base::RefCountedMemory>& bitmap_data,
+    FallbackIconStyle* style);
+
 }  // namespace favicon_base
 
 #endif  // COMPONENTS_FAVICON_BASE_FALLBACK_ICON_STYLE_H_
diff --git a/components/favicon_base/favicon_callback.h b/components/favicon_base/favicon_callback.h
index 7616a11..96029f1 100644
--- a/components/favicon_base/favicon_callback.h
+++ b/components/favicon_base/favicon_callback.h
@@ -13,6 +13,7 @@ namespace favicon_base {
 
 struct FaviconRawBitmapResult;
 struct FaviconImageResult;
+struct LargeIconResult;
 
 // Callback for functions that can be used to return a |gfx::Image| and the
 // |GURL| it is loaded from. They are returned as a |FaviconImageResult| object.
@@ -29,6 +30,11 @@ typedef base::Callback<void(const FaviconRawBitmapResult&)>
 typedef base::Callback<void(const std::vector<FaviconRawBitmapResult>&)>
     FaviconResultsCallback;
 
+// Callback for functions returning data for a large icon. |LargeIconResult|
+// will contain either the raw bitmap for a large icon or the style of the
+// fallback to use if a sufficiently large icon could not be found.
+typedef base::Callback<void(const LargeIconResult&)> LargeIconCallback;
+
 }  // namespace favicon_base
 
 #endif  // COMPONENTS_FAVICON_BASE_FAVICON_CALLBACK_H_
diff --git a/components/favicon_base/favicon_types.cc b/components/favicon_base/favicon_types.cc
index 0188f1e..e69f1d7 100644
--- a/components/favicon_base/favicon_types.cc
+++ b/components/favicon_base/favicon_types.cc
@@ -4,6 +4,8 @@
 
 #include "components/favicon_base/favicon_types.h"
 
+#include "components/favicon_base/fallback_icon_style.h"
+
 namespace favicon_base {
 
 // ---------------------------------------------------------
@@ -20,7 +22,13 @@ FaviconRawBitmapResult::FaviconRawBitmapResult()
     : expired(false), icon_type(INVALID_ICON) {
 }
 
-FaviconRawBitmapResult::~FaviconRawBitmapResult() {
-}
+FaviconRawBitmapResult::~FaviconRawBitmapResult() {}
+
+// --------------------------------------------------------
+// LargeIconResult
+
+LargeIconResult::LargeIconResult() {}
+
+LargeIconResult::~LargeIconResult() {}
 
 }  // namespace favicon_base
diff --git a/components/favicon_base/favicon_types.h b/components/favicon_base/favicon_types.h
index ea64754..f7c812a 100644
--- a/components/favicon_base/favicon_types.h
+++ b/components/favicon_base/favicon_types.h
@@ -6,12 +6,15 @@
 #define COMPONENTS_FAVICON_BASE_FAVICON_TYPES_H_
 
 #include "base/memory/ref_counted_memory.h"
+#include "base/memory/scoped_ptr.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/image/image.h"
 #include "url/gurl.h"
 
 namespace favicon_base {
 
+struct FallbackIconStyle;
+
 typedef int64 FaviconID;
 
 // Defines the icon types. They are also stored in icon_type field of favicons
@@ -72,6 +75,22 @@ struct FaviconRawBitmapResult {
 // HistoryBackend::SetFavicons().
 typedef FaviconRawBitmapResult FaviconRawBitmapData;
 
+// Result returned by LargeIconService::GetLargeIconOrFallbackStyle(). Contains
+// either the bitmap data if the favicon database has a sufficiently large
+// favicon bitmap and the style of the fallback icon otherwise.
+struct LargeIconResult {
+  LargeIconResult();
+  ~LargeIconResult();
+
+  // The bitmap from the favicon database if the database has a sufficiently
+  // large one.
+  FaviconRawBitmapResult bitmap;
+
+  // The fallback icon style if a sufficiently large icon isn't available. This
+  // uses the dominant color of a smaller icon as the background if available.
+  scoped_ptr<FallbackIconStyle> fallback_icon_style;
+};
+
 }  // namespace favicon_base
 
 #endif  // COMPONENTS_FAVICON_BASE_FAVICON_TYPES_H_